I have found that Open Sound System works properly. For those who still struggle with FreeBSD audio on Intel 945G/P chipsets can get this driver. It's free for home use.
I have also found out, today, my motherboard was one of the cheapest motherboards, which turns out to be a "bad" motherboard. Few things I have spotted:
Realtek HD Audio
Operating systems do not support this card without installing proper HD audio codec (I think). Realtek did not release any FreeBSD driver for the card, and I know BSD people were working on this card to get it working.
This NIC is not recognized by FreeBSD. Marvell-Yukon, however, provides driver for FreeBSD. I have had problems on Windows with this card, too. When Windows' stupid security measure starts (it stops TCP/IP service after computer reaches a limit of failed connections in some certain time), what I was normally doing is unplugging cable and plugging back on again. This simply does not work on Windows XP SP2 (with latest patches, including this WGA crap (or spyware, whatever) installed). I think there is something wrong with the driver, because when interface goes down, it never comes up again. If it starts down, it comes up, no problem with this.
This motherboard is obviously slower than other 945 series. I am running a dual core 2.8GHz, with 2GB RAM, but it is still too slow (on BSD as well).
I do not know whether it's related to my hardware, but on Windows, I am having toooooooo much page faults and my disk spins like crazy, can be heard from the corridor, even if I close my door.